Kate's Big Three Arc on 'This Is Us' Won't Be Airing Tonight — Here's Why

Viewers of This Is Us have had to deal with the mystery surrounding the debate over who Kevin Pearson's baby mama is, why Randall and Kevin aren't speaking in the future, and Rebecca's memory issues just on Season 4 alone, but there's truly been no more dramatic storyline than the circumstances surrounding Kate's relationship with Mark in the flashbacks.

While we know that Kate and Toby got ultimately married and had a baby together in the present, Kate's earlier relationship with her music store co-worker Mark has fans worried. Season 4 has a Big Three arc that centers on each of Jack and Rebecca's three kids, and in both Randall and Kevin's episodes, we learned bits and pieces about Kate's tumultuous relationship with Mark.

After learning that Rebecca called her sons to help her after Kate and Mark headed to the Pearson's cabin in the flashback, fans are thinking that something gravely wrong is going on. But, viewers won't get an answer until Feb. 11, when the show returns from a brief hiatus.

Why isn't This Is Us on tonight? Read on for the reason as to why the show won't be airing a new episode on Feb. 4 and what the cast and crew has said about what to expect from Kate's big episode and the rest of the season. 

Though Kate's flashback storyline with Mark has had fans stumped since nearly the start of Season 4, viewers won't be getting any resolution on Feb. 4 during the usual time slot This Is Us. Fans will have to wait until Feb 11 to learn about what happened at the cabin when Kate was a teenager, and why her marriage to Toby is crumbling in the present.

The reason for this delay is because the State of the Union address is taking place on Feb. 4 at 9 p.m. on NBC. 

President Trump will be giving his third State of the Union speech, which will cover where the economy, military, and other facets of his leadership are at in the year since his last address. The speech takes place at the beginning of each calendar year, and it generally interrupts regular TV lineups. 

This Is Us will go back to its regular date and time one week after the State of the Union address. 

Though This Is Us fans are upset that they won't see the conclusion of Kate's storyline for another week, executive producers Elizabeth Berger and Isaac Aptaker spoke to Entertainment Weekly about how the wait will be worth it. They explained that viewers will finally get to see how Kate's turmoil with Mark in the past is actually affecting her marriage to Toby in the present. 

"They are definitely two important relationships that have greatly informed this woman and her life," Elizabeth explained. "And I think all of those intense teenage relationships tend to stick with us and cause patterns to form and leave these impressions that never really go away. So, we will be seeing how some of Kate was formed through this relationship with Marc — and how that may impact her current relationship."

Isaac also teased that one scene from Kate's upcoming episode will include something that fans have been requesting for years.

"Mandy and Chrissy have a scene together where they do something that we’ve maybe been asked about more than anything if we’re ever going to have on the show," Isaac said. 

While some are speculating that the pair will sing together, it remains to be seen what will happen on Kate's Big Three episode.

This Is Us airs on Tuesdays (except for Feb. 4) at 9 p.m. on NBC.